Small laboratory animal models such as mice, rats and hamsters are widely used throughout the biomedical research community at Washington University and other scientific institutions. With the recent revolution in molecular biology, transgenic laboratory animal models - in particular mice - have become an indispensable part of the biomedical research armamentarium. However, the identification and development of methods for evaluating the characteristics of interest within animal models remains a significant challenge. Nondestructive imaging procedures, such as those offered by magnetic resonance imaging, positron emission tomography, computed tomography, and optical imaging are especially valuable in this regard. The Biomedical Magnetic Resonance Laboratory has responsibility for essentially all small-animal MRI at Washington University. The BMRL is headquarters for the Washington University Small Animal Imaging Resource, which was established specifically to address the need for MRI, PET and, more recently, optical tomography and CT of small laboratory animal models. The National Cancer Institute provides substantial support for WUSAIR through its Small Animal Imaging Research Program. The BMRL is also associated with Washington University's Alvin J. Siteman Cancer Center, an NCI Comprehensive Cancer Center, as headquarters of its Small Animal Imaging Core. This Shared Instrumentation Grant requests funds to upgrade one of the BMRL's core instruments, a 12-year-old, 4.7-tesla, 33-cm small-animal MRI scanner, to state-of-the-art capabilities. This upgrade includes new components from Varian NMR Systems (scanner console), Magnex Scientific (gradient/shim-coil assembly), Copley Controls (gradient amplifier), and Resonance Research (shim power supply) The small- animal MRI scanner being upgraded via this SIG application will be sited, operated, maintained, and administered within the intellectual and administrative infrastructure of the BMRL. The upgraded scanner will provide a platform for a host of studies (and user training) required for support of in vivo and ex vivo (fixed tissue) MRI protocols. Thus, the extensive community of NIH-funded researchers who require access to the BMRL scanners will immediately and directly benefit from the requested magnetic field gradient and console upgrades. RELEVANCE: Small laboratory animal (e.g., mice) disease and injury models are widely used throughout the biomedical research community. Magnetic resonance imaging, the subject of this proposal, allows a safe, non- invasive, non-destructive means to evaluate these models and translate findings to patients. [unreadable] [unreadable] [unreadable]